Around 1978 Mike Matthew's Electro-Harmonix company was doing very well and had offices in Tokyo, London, and Toronto, in addition to the New York office. The 50,000 square foot Manhattan factory was generating five million in annual sales. The traditional four transistor Big Muff circuit was radically changed at this time to a new circuit that used op-amp chips and one less gain stage, in an effort to reduce manufacturing costs. Op-amps are operational amplifiers, also known as ICs (integrated circuits or chips). It is likely this version and the V5 tone bypass version listed below were made simultaneously, with the V4 version being phased out in 1978 or 1979. To economize production, two of the three circuit boards used in the V4 Big Muff were also used in the Little Big Muff pedal enclosure. They both used the same circuits, only the LBM was made without tone and sustain pots.

I am including this as a legit Big Muff, even though it was not built on the classic Muff four-stage tone circuit. It was intended to sound like a Big Muff, and was released in the same box as Version 3, so I feel it must be included as a true Muff version. Plus, I, and many others like them. It has a huge, crushing Big Muff sound. Though not quite the same as the organic transistor tone, is was very unique. Supposedly only a few thousand of this version were made.

GRAPHICS - The box, knobs, and graphics were identical to the second edition Version 3 BIG MUFF, and these V4 Muffs are often confused with the V3. The only way to tell is to look at the circuit board for the two distinct op-amp chips, or to turn the control knobs to see which way the pots are mounted, as illustrated below. V3's all have the pre 1978 configuration, and V4's have the post 1978 configuration.

CONTROLS / KNOBS - Version 4 had the same plastic Daka-Ware control knobs and on/off switch as version 3, but there were also identical knobs used marked HDCO on the underside, and some unmarked knobs used. One major change to note was the was the positioning of the potentiometers on the circuit board. They were changed so that each wrapped around the top edge of the circuit board, allowing each knob to start at zero in the same position (finally!). All big Muffs prior to the V4 had each pot mounted in a different position from the others. This also changed the TONE knob orientation so that bass was on the left and treble was on the right, as it has remained on all subsequent Big Muffs.

CIRCUIT - The V4/V5 circuit was about half the size of the V2/V3 transistor circuit, but there were at least four different pcb layouts used. Early versions of the op-amp circuit board were similar size to the V3 circuit and were marked with "EH-3003B". Then a smaller size pcb was made, marked "EH-1322" and "EH-1322B". Later production changed back to the simple "EH-3003", the same number used on the V2/V3 versions. Three of the four circuit boards, the EH1322, 1322B, and 3003, included extra pads for another volume pot position. The extra pot pads were to allow the circuit board to fit sideways in the Little Big Muff pedal enclosure, which used the same circuit but only had one control knob for volume.

Howard Davis, Manager of Analog Circuit Design for E-H from 1976-1981, claims credit as the circuit designer for this version, as does former EHX designer Michael Abrams. Howard was responsible for over a dozen E-H pedal circuit designs, as well as most the the ”deluxe“ Electro-Harmonix models that appeared in the late 1970s to early 1980s, including the superb op-amp Deluxe Big Muff, Deluxe Memory Man, and Deluxe Electric Mistress. The op-amp Big Muff was assigned to Howard to fill a desire for a simpler, less costly product that would do all that the transistor version did. However, due to the differing distortion characteristics of the op-amps it turned out to have a somewhat "grungier" sound than the transistor design, an effect preferred by some musicians. The circuit was made with one of the popular 741 op-amps and one RC4558 dual op-amp, though occasionally V4 Big Muffs are seen with different chips. Howard's original design schematic, dated 4/6/1978, included the tone bypass switch, seen on the V5 Big Muff. He does not recall ever designing a non bypass version, but sometimes changes were made to his designs by others at E-H that he was not made aware of, which may explain why the V4 version did not include the tone bypass function. The feature was included on the Version 5, which was likely made at the same time as this version, based on the fact that they both share three of the four diferent circuit boards used, and similar pot dates.

When I asked Howard about how the op-amp version originated and how he got involved in the redesign, he had this to say -

"As chief engineer for Electro-Harmonix, basically my direction ( from E-H owner Mike Matthews) was to design a Big Muff using op-amps. He often would just tell me to "think about" something, and I took it from there. The transistor version is somewhat sweeter sounding (than the IC version). Grunge and punk-style players though often want something with more edge or coarseness, more crunch, and the IC Big Muff is just what they want. It can give you the Mountain sound - the guitar rough around the edges, but with the rest of the band playing, melodic overall."

Howard is still involved with his E-H creations, doing custom mods and repairs to vintage Big Muffs, as well as his other E-H pedals. Here is a mini interview with Howard about his Big Muff circuit from 2009.

There was NO LED light on this version. Power was from a 9V battery or an AC power adaptor jack. The top had to be removed to change the battery. These had four rubber feet and shipped in a corrugated cardboard box.Most of the pots are dated 1977, though these were all likely made in 1978.

CLONES OR SIMILAR PEDALS - The Deluxe Big Muffs from the late 1970s also used a nearly identicals circuit, as well as some of the Little Big Muff pedals Electro-Harmonic made in the same time period. Later replicas are the Euthymia ICBM, Stomp Under Foot Op-Amp Fuzz. See DiscoFreq's Effects Database for a thorough listing of all the Big Muff clones and variants throughout the years.

THE V4 SOUND- This is a great distortion pedal with a big sound and much of the same scooped mids character of the previous transistor versions, but not exactly the same sound. Overall the V4 has a slightly flatter mid range, less gain, and less bottom end than the V3 and V6 transistor versions, but the V4 is also much quieter than a V3 or V6 when the sustain is maxed. I think the transistor versions are much more organic and reactive to pick attack and harmonics than the V4, but the V4 still sounds great for crushing, grungier, wall-of-sound distortion, heavy distorted rhythm playing, and heavy leads. They are probably not as good for palm muting as the transistor versions and the fzz or buzz that is typical with a Big Muff has a slightly more machine-like metallic feel than the transistor versions. As with the transistor versions, the scooped tone makes them easy to get lost in a band mix when playing live with certain amps.

Unlike the transistor versions, the V4 tone is very consistent from unit to unit. Some units may have a noticable volume/gain boost when the pedal is switched off due to the fact that these old Big Muffs do not bypass the signal even when off. The signal still goes through and is amplified by the active op-amps, which can sometimes add a gain boost. Adding a true bypass switch can eliminate this problem. This is likely the Big Muff circuit heard on most of Smashing Pumpkins' Siamese Dream and Pisces Iscariot albums, so that should give an idea of the potential of this version. This is the rarest of the two op-amp Big Muff versions.

BILLY CORGAN AND THE WALL OF MUFF SIAMESE DREAM TONE - A very popular Big Muff user was Billy Corgan, who used the Muff to very good effect on Smashing Pumpkins' song Siva from the Gish album, the entire Siamese Dream album, and most tracks on Pisces Iscariot, recorded in 1992-93. Many of us Big Muff users thought this had to be a Triangle Big Muff. Creative urban Muff legend has it that Billy used a black Sovtek Russian Big Muff with a "creamy dreamer" mod, though Billy has denied this, the first black Sovtek BMP came out around 1998, and the creamy dreamer pedal did not even exist until around 1999, all years AFTER Siamese Dream was recorded. Billy has referred to his Big Muffs as "vintage", which Russian Muffs were not, and he has also stated at least twice that this was a "stock" Big Muff. He revealed in late 2009 (on the Ain't No Sleep When You're Living the Dream blog) that he used a vintage USA Big Muff through a Marshall JCM 800 100 watt head, modded to fit KT88 China tubes for more clean head room and less amp distortion, rather than the stock EL-34 tubes. His photo of the actual Big Muff showing his exact settings indicate it is the V4 op-amp (IC) Big Muff. The graphics match second edition V3 and V4 Big Muffs, but the tone and sustain pot sweep only allow the knobs to be postioned as Billy set them if this were a stock V4 Muff, assuming the pots have not been replaced or modded prior to Billy buying it, or this is not some oddball transistor Big Muff inside the enclosure common to one of the other units, which do appear from time to time. Based on listening to the isolated guitar tracks, and my experiments achieving this tone using some of the same gear Billy described, I believe this to be a V4. In 2011 Billy asked pedal maker Devi Ever to build a custom fuzz pedal allowing him to blend the op-amp BMP circuit and a Super Fuzz circuit, indicating that he does prefer the op-amp version. Billy had two Big Muffs for the Siamese Dream sessions, pictured below.

Shown above - Billy Corgan showing his Siamese Dream era V4 Big Muff and a V5 (or possibly tone bypass V3). On the right is an MXR Distortion II that was fed into the Big Muff for solos, showing the actual settings used (screen shots from the Oceania recording sessions in 2011)

Billy has stated that he got the idea of using a Big Muff after hearing a fellow Chicago band, Catherine, rehearsing, with all three guitarists using Big Muffs simultaneously. Both bands used the same rehearsal space, and members of both bands have played on each other's recording at various times in the studio. Billy Corgan even produced Catherine's first EP in 1993. Corgan may have gotten the idea for the Big Muff sound from hearing Catherine, but many of Catherine's songs sound eerily the same as the SP Siamese Dream sounds, with identical guitar tones and playing styles. In fact, Catherine was often called a Smashing Pumpkin's clone. Both bands seem to have been heavily influenced by each other, borrowing sounds, despite the fact that Billy has stated that each band trusted the other not to steal their sounds.

Here is what Billy had to say about his op-amp Big Muff (pictured below) and the SD sound: "Almost all the heavy (Siamese Dream) tracks were recorded through this, solos included. Many songs would have as many as eight fuzz guitars going at once (rhythms were multi tracked, sometimes in different octaves). It was very difficult to record the tracks with this sound, but once it went right it was BLAMMO, a huge, huge sound. The settings you see in the picture are the exact settings - if you look close enough you can still see the pencil marks on the volume and tone. I had all sorts of theories of how to best use this pedal, including the idea that it only sounded its 'best' when used with a battery." "When we did Siamese Dream I developed a technique of plugging my Big Muff pedal into the low sensitivity input of a 100 watt Marshall JCM 800, with the master volume on full and the preamp volume on barely at all (treble at 3-4)." "The sound of the combo of the Bat Strat ('57 Strat reissue with Lace Sensor pickups), the Big Muff, and the Soul head with Mars cabinet (Marshall JCM 800 100w head and cab) is still unmistakable..." "I would say that 98% of all guitar parts on the first two albums were done thru this amp/speaker combo. In order to change the sound, the Stratocaster parts would be recorded through a shure 57 on the bottom right speaker, and the Les Paul parts would be recorded through a Sennheiser 421 on the top left speaker. This subtle difference between what speaker we would use created the sense of playing thru a different amp set-up even though obviously I wasn't." "Finally, the nasal, squeezed up lead tone that I use so often, as on 'pissant,' for example, I ripped off from Michael Schenker! I used an EH Micro-Synthesizer and some unknown fuzz pedal, plus an MXR Phase 100." "Funny story - I used to shop at this music store in San Francisco, and in the early '90s they were selling these (vintage Big Muff) pedals back then for about 40 bucks because nobody wanted them. About a year after Siamese came out, '94 I guess, I went to the same store to see if they still had any. The guy behind the counter knew me from before, and told me, 'yeah, i got a couple.' I said 'ok, how much?' '200 bucks' he said casually, which at that time was A LOT for a vintage pedal. '200 bucks!!!! Why are they so much? Are they rare or unusual?' He said, 'no, but ever since you talked about using them we've sold about 75 vintage muffs. Sorry man, they're all looking for your sound!'

The band only had one Big Muff in the beginning, that guitarists Jamies Iha and Billy shared. They also used a vintage green Electro-Harmonix Electric Mistress. At the time of Siamese Dream recordings, they owned 2 different Big Muffs, the V4 version, and what appears to be a tone bypass V5 version, or possibly a tone bypass V3. For many of the solos on Siamese Dream Billy used the E-H made Micro Synth with the Big Muff, an MXR Distortion II into a Big Muff, and an MXR Phase 100 with the speed dialed down for lead tones. He also had an E-H Ring Modulator, Fender Blender, and numerous other fuzz and modulation pedals in the studios.

Vintage V5 Big Muffs and Deluxe Big Muffs also use nearly the same op-amp circuit as the V4 and are perfect for these tones. It should be noted that although the op-amp BMP sound was unique, similar tones can be achieved using just about any late 70's Big Muff, some early 70's V1 or V2 Muffs, or even the later NYC reissue Big Muff. On the boutique side, an SUF Pumpkin Pi or Euthymia ICBM are clones of op-amp Big Muffs. A Skreddy Mayo, the Blackout Effectors Musket, or the Way Huge Swollen Pickle also do a good job. Dark, bassy, very mids scooped Big Muffs work best for these tones.

Shown above - Billy Corgan's Big Muff shown with his exact settings, made famous on the Smashing Pumpkins' Siamese Dream album. Graphics and knob positions indicate that this is the V4 op-amp Big Muff. Note the price sticker and white knob position marks on the older Machina tour photo shown on the left, which is the same Big Muff shown on the right.

Shown above - V4 op-amp Big Muffs with pots dated 1977. The V4 features an on/off switch and the words ON and Off appear on the graphics, which are identical to the V3 Big Muff. The only way to tell the difference is to examine the circuit board, which will have two op-amp chips rather than four transistors.

Shown above (left to right) - Big Muffs with the first op-amp circuit board, manrked 3003B, all with pots dated 1976 or '77.

Shown above (left to right) - Another V4 Big Muff with 3003B circuit board and 1977 pot dates.Note the positioning of the potentiometers so that each wraps around the top edge of the circuit board allowing the knobs to start at zero in the same position. All Big Muffs previous to the V4 had each pot mounted in a different position from the others.

Shown above (left to right) - V4 op-amp Big Muff with the second circuit board, marked EH-1322, and 1976 pots. Note the two black op-amp chips on the circuit board, each with eight connection leads. The V5 tone bypass version was made with this exact same circuit board at the same time. Note the three extra volume pot pads you can see on the populated side of the board. This was to accommodate the Little Big Muff, which shared the same pcb. The LBM only included a volume pot, and was mounted sideways in the enclosure, requiring the volume pot to be mounted differently.

Shown above (left to right) - Two V4 op-amp Big Muffs with EH-1322 circuits, and 1977 pots. The V5 tone bypass version was made with this exact same circuit board at the same time.

Shown above (left to right) - V4 op-amp Big Muff with the fourth curcuit board, marked EH-3003, 1978 pots, and hockey puck knobs. The V5 tone bypass version was made with this exact same circuit board at the same time. Note the extra volume pot pads, which allowed this board to be used in the Little Big Muff enclosure. The LBM only included the volume pot, and was mounted sideways in the enclosure.

The V5 tone bypass version and the V4 on/off switch version (listed above), were made and sold simultaneously. They both share the same circuit boards and similar pot dates. The V3 transistor based Big Muff with tone bypass switch was also made at the same time as this version, making it appear E-H had three version of the Big Muff Pi on the market simultaneously! The tone bypass mod was added point-to-point on the back side of these three circuit boards. Note that this is a "tone bypass", not "true bypass" which is something completely different. None of the vintage Big Muffs were true bypass. The tone bypass function gave a flatter EQ with more mids, more volume, but completely disabled the tone control.

GRAPHICS - Identical to the V4 Big muff, except “TONE BYPASS” was labeled on the top of these V5 units instead of "OFF ON".

CONTROL KNOBS - The Daka-Ware style knobs that had been used since Version 2 were changed during production of the V5, and are also seen on tone bypass V3 models. After years of using knobs from other suppliers, E-H decided to invest tooling money to make their own injection molded knobs in Taiwan. These were the familiar flat-topped, hockey puck shaped knobs with white indicator marks that are still seen on the V9 NYC reissue versions being produced since 2001, and many other E-H pedals. Both knob types were used for the V5 version.

CIRCUIT - The on/off switch seen on Version 4 was also made to be a tone bypass switch for Version 5 of the Big Muff, which was likely in production at the same time as the V3 tone bypass trasistor version and the V4. Howard Davis' orignal circuit design for the V4 op-amp Muff included the tone bypass function. Switching the bypass on disabled the tone circuit. The tone knob had no effect when in bypass mode. Otherwise this was practically the same unit as the Version 4 Big Muff.

There were four different circuit board layouts used for the V4 version, and three of those were used for this tone bypass version, indicating that both the V4 and V5 were offered for sale at the same time. Note that three of the four circuits required a .22uF/224k cap and two 47k resistors to be soldered point-to-point on back side of the circuit board for the tone bypass mod, but the fourth circuit layout incorporated this complete schematic into the circuit design so all components could be mounted on the populated side. It is interesting to note that Howard Davis thinks the tone bypass feature was already in use on the V3 when he designed the op-amp V4/5 version, which explains the V3 transistor Big Muffs I have seen that included this feature. This circuit design was also morphed into the Deluxe Big Muff circuit, also using op-amps rather than transistors.

To economize production, all three V5 circuit boards included extra pads for another volume pot position. The extra pot pads were to allow the circuit board to fit sideways in the Little Big Muff pedal enclosure, which used the same circuit, but only had one control knob for volume.

There was NO LED light on this version. Power was from a 9V battery or an AC power adaptor jack. The top had to be removed to change the battery. These had four rubber feet and shipped in a corrugated cardboard box. Most of the pots I have seen are dated 1978, though I have been told these were still being made and sold as late as 1980.

CLONES OR SIMILAR PEDALS - The Deluxe Big Muffs from the late 1970s also used a nearly identicals circuit, as well as some of the Little Big Muff pedals Electro-Harmonic made in the same time period. Later replicas are the Euthymia ICBM, Stomp Under Foot Op-Amp Fuzz. See DiscoFreq's Effects Database for a thorough listing of all the Big Muff clones and variants throughout the years.

THE V5 SOUND- Practically identical sound to the V4 op-amp Big Muff described above. This version included a 'tone bypass' switch (not true bypass). With the bypass switched on it removes the tone circuit, making a huge, peircing distortion. The bypass also allows a flatter EQ that makes it have brighter mid tones. I think the tone in non bypass mode sounds better as the tone control is key to the Big Muff sound, but some people like the bypass. There is a slight 6-7 decibel boost when in bypass mode. This is the most common of the two op-amp Big Muffs.

CLICK A PHOTO TO ENLARGE

Shown above - V5 tone bypass, op-amp Big Muffs. The example on the bottom includes the new flat-topped "hockey puck" knobs that E-H had manufactured in Taiwan. Pots date 1978. Many V5 Big Muffs were still made with the old Daka-Ware style knobs as you can see in the top photos.

Shown above (left to right) - V5 op-amp with Big Muff with 1978 pots, using the second V4 circuit board marked EH-1322. Note the capacitor and two resistors mounted on the trace side of the pcb, common to three of thr four circuit boards used for the V4/V5Big Muffs. This was the tone bypass mod added for this version. This exact same circuit board was used for the V4 version, minus these components, and also for the Little Big Muff, minus these components and the tone/sustain pots.

Shown above (left to right) - A few V5 op-amp Big Muffs with EH-1322 circuit boards, 1978 pots, and tone bypass cap/resistor components mounted on the trace side. Note the three unused pot pads on the left side of the populated side of the pcb, there to allow this same circuit to be used in the Little Big Muff

Shown above (left to right) - The op-amp Big Muff circuit board was changed again to this much cleaner circuit, now simply marked EH-3003. The cap and resistor components mounted on the trace side of the previous three pcbs for the tone bypass function were now incorporated into the complete circuit design. 1979 pots, and old style Daka-Ware knobs. This exact same circuit board was used for the V4 version made at the same time, and the Little Big Muff.

Shown above - Late V5 op-amp Big Muffs with EH-3003 circuit board. Pots dated 1978 (top left), 1979 (top right) and 1980 (bottom). These also have the new "hockey puck" shaped knobs that all Big Muffs were transitioning into using after 1978. These were the last op-amp Big Muffs made before they were phased out around 1980 or '81 and the transistor version was brought back.